Method to prevent saturation of an inductor coil and inductor coil circuits for realising such a method

Abstract

A method to avoid saturation of the magnetic core (M) of an inductor coil (L) includes the steps of providing a bypass circuit (BP) across said inductor coil (L) for bypassing a DC current to said coil. Such a bypass circuit includes a regulating circuit (RE) to control the amount of DC current which is bypassed, and may further include an active gyrator (G) for the bypass of the DC current. This invention is applicable to one single coil (L) or to any circuit including a series connection of coils. In the latter case one or more bypass circuits may be provided across either one or more series connected coils.

1 . Method to avoid saturation of the magnetic core (M) of an inductor coil (L), said method including the steps of providing a bypass circuit (BP) across said inductor coil (L) for bypassing a DC current to said coil.  
   
   
       2 . Method according to  claim 1 , wherein said step of bypassing said DC current is performed via the provision of a variable current source.  
   
   
       3 . Method according to  claim 1 , wherein said method further includes a step of providing a regulation circuit (RE) for regulating the level of the DC current which is bypassed.  
   
   
       4 . Inductor circuit (LBP) including a coil winding (L) around a magnetic core (M) 
 characterised in that    said inductor circuit (LBP) further includes a bypass circuit (BP) for bypassing a DC current through said coil winding (L).    
   
   
       5 . Inductor circuit (LBP) according to  claim 4 , wherein said bypass circuit (BP) comprises a variable current source.  
   
   
       6 . Inductor circuit (LBP) according to  claim 5 , wherein said bypass circuit (BP) includes a gyrator circuit (R 1 ,C 2 ,T).  
   
   
       7 . Inductor circuit (LBP) according to  claim 4 , wherein said inductor circuit further includes a regulation circuit (RE) for regulating the level of the DC current (I DC  ) which is bypassed.  
   
   
       8 . Inductor circuit (LBP) according to  claim 7 , wherein said regulation circuit (RE) includes means (C 1 ) to create a DC voltage drop across said variable current source.  
   
   
       9 . Inductor circuit according to  claim 9 , wherein said regulation circuit includes a capacitor (C 1 ).  
   
   
       10 . Inductor circuit according to  claim 9 , wherein said regulation circuit includes a resistor.  
   
   
       11 . Circuit (F) including a series connection of coils (L 1 , L 2 ), characterised in that said circuit (F) further includes at least one bypass circuit (BPF) according to  claim 5  across one or more of said coils (L 1 ,L 2 ).